Explanation:
What caused the pits, ridges, and gullies on
otherwise smooth Martian terrain?
One hypothesis is water.
The lack of
craters at this
mid-latitude location indicates that the terrain
is quite young by geological standards,
perhaps only 100,000 years old.
Were the terrain since saturated by water ice,
that ice would soon evaporate into the
thin Martian air.
Left over, however, might be fragile
cake-like sand that can be broken up by wind into pits and ridges.
Consequences of
this hypothesis include that even the
Martian equator
undergoes epochs of relative wet and dry,
and that future spacefarers might be able to find
water (ice) in a relatively
mild climate near the
Martian equator.
Pictured above is young-ridged terrain that
also shows evidence of a
downhill flow.